Jayich Research Lab - news

Group Photo - 2025

Wed, 10 Sep 2025 00:00:00 +0000

Laser cooling and trapping of short-lived radium ions

Mon, 22 Jan 2024 00:00:00 +0000

Under Mingyu Fan’s leadership, we realized the first laser cooling and trapping of ²²⁴Ra⁺ ions, an isotope of radium which has a half-life of only 3.6 days. This achievement marks a significant step towards the lab’s goals of probing new physics with short lived radium ions. Radium atoms were produced from an effusive oven source, the culmination of several years of development led by Mingyu Fan and Max Ladabaum. A marked outcome of this research is the reliability of our radium atom source, which continues to produce radium atoms on demand nearly a year after being sealed in vacuum. The team first observed fluorescence of neutral ²²⁴Ra atoms in a vacuum chamber test bed, which Haoran Li and Spencer Kofford later used for a spectroscopy of the atom’s 483 nanometer transition. This frequency measurement enabled us to effectively photoionize ²²⁴Ra once the oven source was moved to the vacuum chamber that houses our ion trap. Mingyu Fan and Roy Ready spearheaded tests to determine effective methods to trap radium ions, including various photoionization schemes and oven operating temperatures. With the ability to routinely trap single and multi-ion chains for days, we are able to see ions occasionally disappear, presumably due to nuclear decay. The article describing this work was published in Physical Review Research, and is also available on the arXiv.

Tray Launcher, our first foray onto PyPI

Mon, 29 Aug 2022 00:00:00 +0000

The Tray Launcher is our first project that has been published to PyPI. It makes management of Windows BAT files easier, condensing them into a single menu in the system tray instead of having many terminals cluttering the taskbar. The project was Mingyu’s idea, and the first programming work was done by Kate Sheldon, who was a high school student at the time, with guidance from Ganden Schaffner. Kate made a solid software foundation that Huaxu Dan, a first-year undergrad at UCSB, built upon to get to the point where the software was reliable enough for a public release. Currently the software is on version 1.0.7. The code is available here on GitHub.

Measurement of the Ra⁺ 7p ²P_3/2 state lifetime

Mon, 04 Apr 2022 00:00:00 +0000

Mingyu Fan led a team to realize the first excited state lifetime measurement in the radium ion. The measured lifetime is in good agreement with theoretical calculations and will enable calculation of the differential scalar polarizability of the narrow linewidth optical clock transition. Craig and Asad helped to build and operate the experiment, and undergraduates Chaoshen and Sam made made key contributions to stabilizing laser powers. The Article describing this work was published today in Physical Review A, and is also available on the arXiv.

A radium ion optical clock

Thu, 20 Jan 2022 00:00:00 +0000

Craig Holliman led a team, including collaborator Sam Brewer, to realize the first optical clock based on the radium ion. Radium is a famously unstable element, so it is a bit ironic that our group has made a high-stability clock using one of its optical transitions. But, looking more closely the radium ion has appealing features for a trapped ion clock. The wavelengths for working with trapped radium ions are very user-friendly: all of the necessary transitions could be addressed with low optical powers using integrated photonic sources. This makes the system promising for a compact and low-power optical clock. The ion’s high mass is good for addressing some of the leading issues with optical clocks. In the future when we begin working with radium-225 there will be built-in insensitivity to nefarious magnetic field noise through the isotope’s particular electronic structure. A radium ion clock could also be used to constrain the time variation of fundamental constants. The Letter describing this work was published today in Physical Review Letters, and is also available on the arXiv.

Virtual AMO Seminar

Fri, 02 Apr 2021 00:00:00 +0000

It was an honor to represent our group and present our work for the Virtual Atomic, Molecular, and Optical physics Seminar series (VAMOS). In the talk, “Radium ions and cold radioactive molecules”, I discuss our recent radium ion measurements, our progress with radium-based molecules, and some of the motivations for our research, as well as our plans moving forward. The post talk discussion (not recorded) with students, postdocs, and a few P.I.’s was a highlight - lots of fun ideas were explored! Thank you to the VAMOS organizers for giving me this opportunity.

Radium monomethoxide in the news

Mon, 29 Mar 2021 00:00:00 +0000

The work by Nick Hutzler and Phelan Yu on RaOCH₃⁺ (radium monomethoxide) and its potential to address the mystery of the Universe’s matter-antimatter asymmetry was featured in an article on phys.org.

Mingyu presents at CERN

Thu, 11 Mar 2021 00:00:00 +0000

Graduate student Mingyu Fan gave a seminar to CERN’s ISOLDE Physics Group. ISOLDE has made seminal measurements on radioactive molecules, in particular RaF. They were happy to hear about Mingyu’s recent paper where we demonstated the controlled production of cold, trapped radioactive molecules.

Radioactive molecules on demand

Mon, 11 Jan 2021 00:00:00 +0000

Our work on the controlled synthesis and detection of radioactive molecules was published today in Physical Review Letters. In the paper we demonstrate a new all-optical technique for identifying trapped ions by their mass in an ion trap. The technique, optical mass spectrometry, has several advantages: it is non-destructive and fast. We applied the technique to detect the synthesis of radioactive molecules that are exceptional sensors for addressing open questions related to time symmetry violation.

The paper was the culmination of an incredible process that started with grad student Mingyu Fan one day noticing that the trapped ions he was working with were excited to large motional states if he changed one of our laser’s frequencies by a small amount (~10 MHz). We discussed and I encouraged Mingyu to explore what he had stumbled upon by chance. In short order Mingyu had figured out how to convert a signal from the amplified motion into a mass of the trapped ions. Mingyu then worked out the mechanism behind the motional amplification (see the paper for an explanation). We then decided to apply this new ion identification technique to radioactive molecules, which we were confident we could make, but didn’t have a great means to confirm production until this point. Mingyu and Craig produced RaOH⁺ and RaOCH₃⁺ by reacting trapped radium ions with trace quantities of methanol that was controllably leaked into the vacuum chamber. These molecules are great for addressing a pair of old and pressing problems: first, how is it that there is a massive imbalance between matter, which is abundant, and antimatter, which is practically nonexistent, in the Universe - the Baryon asymmetry problem, and second, why does quantum chromodynamics seemingly preserve charge conjugation and parity symmetry, known as the Strong CP problem.

The figure, by Max our resident artist, is a depiction of optical mass spectrometry where a pair of bright laser-cooled radium ions surround an unknown dark ion. Photons (teal) are detected and converted into a signal (red) that tells us the mass of the unknown ion.

In addition to using optical mass spectrometry with radium and radioactive molecules, a team led by undergraduate Xiaoyang Shi applied the technique to identify the four stable strontium isotopes in the significantly different environment of a high frequency ion trap. It was great to have so many people in the lab and to utilized both of our ion traps for this work. I was also happy that Xiaoyang was able to get data with the trap he built before he graduated - he has since started physics grad school at MIT.

The motivation to produce RaOCH₃⁺ stemmed from a conversation in the fall of 2019 with Nick Hutzler. Later, Nick and graduate student Phelan Yu started working on a paper about this molecule for its potential sensitivity to new physics. It was special to submit our paper jointly with Nick and Phelan’s work to PRL, and go through the review process in parallel with them. Our papers were both featured as Editor’s Suggestions, and Ronald Garcia Ruiz wrote up a very nice APS Physics Viewpoint article about the letters.

The work was also featured in the UC Santa Barbara Current in an article by Harrison Tasoff - Enlightening Dark Ions.

In the lab we’re hard at work on the exciting next steps!

A Ra⁺ transition measurement and first undergraduates are on a paper

Fri, 30 Oct 2020 00:00:00 +0000

Great news, the lab has now had its first set of UC Santa Barbara undergraduates on a publication that came out today in PRA. The work measured a specific transition in Ra⁺ to resolve a discrepancy between previous values by means of directly driving the transition in question. Grad student Craig Holliman spearheaded the entire effort, really leading the others scientists on the paper. As an advisor it was great to watch Craig take full ownership of this experiment, organize people to configure the experimental setup, write code for data taking, take the data, and perform the data analysis. Undergrad Michael Straus made critical contributions to the data analysis, and undergrad Asad Contractor was instrumental in setting up the experiment, taking data and helping refine the manuscript that Craig wrote.

Moore Foundation Fundamental Physics Innovation Award

Mon, 12 Oct 2020 00:00:00 +0000

The Gordon and Betty Moore Foundation have give me a Fundamental Physics Innovation Lectureship Award to visit Michigan State where I’ll be hosted by Jaideep Singh. I’ll present on the possibility of using molecular ions, in particular radioactive molecules with heavy octupole deformed nuclei, for searching for new physics beyond the standard model. We’ll discuss the possibility of setting up a tabletop ion trapping experiment at the Facility for Rare Isotope Beams which could study rare isotopes and molecules containing such isotopes at high precision.

New permanent electric dipole moment measurement technique published in PRL

Thu, 08 Oct 2020 00:00:00 +0000

In collaboration with Amar Vutha and his student, Mohit Verma, we worked on a new proposed permanent electric dipole moment (EDM) measurement technique that was published today in PRL. EDMs are at the forefront of the search for new physics beyond the Standard Model of particle physics to explain several major open issues, including the Universe’s lack of antimatter. In the early history of the Universe matter and antimatter were created in nearly equal quantities, recombined and annihilated (this is what happens when matter and antimatter collide), and a bit of matter was left over, ultimately the material that we are made of. The known laws of physics are not enough to explain this excess of matter over antimatter, and thus we need to look to new physics to explain this discrepancy. One of the conditions for this is new physics that violates time symmetry. When time symmetry is broken a system looks fundamentally different if we reverse the arrow of time. Permanent electric dipole moments violate time symmetry, but so far no EDMs have been found. A brief aside: the electric dipole moment of molecules is not a permanent electric dipole moment, it is an electric dipole moment that has been induced by applied electric fields and does not violate time symmetry. Measuring an EDM would be a clear sign of new physics, and has motivated many searches worldwide for them in systems such as neutrons, atoms, and our personal favorite: molecules. Amar had the brilliant idea that we could utilize special molecular states that are insensitive to magnetic field noise, so-called clock states, and that this would extend the reach of EDM searches to wide classes of molecules that can be prepared with exquisite control. In our group we are really excited to apply this technique to single molecular ions that are highly sensitive to new physics, such as RaOCH₃⁺. The technique should be straightforward to implement in an ion trap where we can apply the requisite control voltages (a small voltage due to small size of the ion trap) on the trap’s end cap electrodes. For a great talk on the proposed technique watch Amar’s talk at FSQT.

Radium cooled to its motional ground state!

Tue, 29 Sep 2020 00:00:00 +0000

In only a couple of years since they realized the first laser cooling of radium ions graduate students Mingyu Fan and Craig Holliman have now cooled radium to its quantum ground state of motion. This is an incredibly exciting starting point for many new research directions with this very heavy atom. Ground state cooled radium means they have essentially full control over the ion, with the ability to very accurately measure the system, or now use phonons, the quantum of motion, to control or readout other co-trapped atoms or molecules. One remarkable aspect of this result is the trap in which the cooling was done: the trap was specifically designed for the first laser cooling and spectroscopy of radium, and the creation of radium molecules, it was in no way designed for cooling to the motional ground state. You can see this in the figure where the motional mode that is cooled is only around 230 kHz where typical ground state cooling happens with motional frequencies around 1 MHz or higher in traps that are much smaller (see our ground state cooling working with the lighter strontium ion). The trap dimenions are r_0 = 3 mm and z_0 = 7.5 mm (the characteristic distances from the radial and axial electrodes to the ion) - this is a very large ion trap by quantum information science standards. The figure shows the probability that the ion can be driven to excited state by light at 728 nm while simultaneously adding or substracting a motional quantum. The small red peak shows that no more phonons can be removed from the system as the average ground state occupancy is 0.12 total phonons. This work was assisted by UC Santa Barbara undergrad Asad Contractor who recently joined the project and is already working on implementing an advanced ground state cooling scheme. With ground state cooled radium Mingyu, Craig, and Asad are actively working on quantum state engineering to further advance the lab’s capabilities.

Undergrads cool to the quantum ground state of motion

Thu, 19 Mar 2020 00:00:00 +0000

Laser cooling micro-mechanical systems to bring them into the quantum regime was the focus of my graduate work in Jack Harris’s group. This involved a ³He fridge that pre-cooled a mechanical membrane to ~400 mK, a high-finesse optical cavity, and coupling free space light through 6 feet of half inch diameter tubing. We were able to use resolved sideband laser cooling to remove all but a handful of quanta. After I graduated, the group made several improvements and cooled to the quantum ground state.

Fast forward to early 2020 and my long-standing dream of ground state cooling is realized by UC Santa Barbara undergraduates Xiaoyang Shi and Michael Straus. When Xiaoyang joined the lab he was tasked with building an RF resonator for a an ion trap. This quickly escalated into Xiaoyang designing and then developing a high frequency ion trap (who else was going to do this work?). Michael joined the project and was charged with making an ultrastable laser for addressing the strontium ion’s optical clock/qubit transition. Over the span of a few short months Michael put together the optical elements to couple light into the cavity and assembled the electrical circuit to realize a PDH lock and stabilize our laser for addressing strontium’s narrow optical clock transition. Over the next several months Xiaoyang and Michael were able to put all of this together with numerous other improvements to our control systems and our understanding of trapped ions. After several attempts and efforts debugging they optimized the system’s parameters and were able to remove the last motional quanta from a single trapped atom, cooling it to its motional ground state. The phonon occupancy is evident in the asymmetry between the red and blue sidebands in the plot - the red sideband is small because the atom lacks phonons. The work was primarily done by Xiaoyang and Michael, but they benefited from assistance and valuable discussions with many in the lab, in particular Mingyu and Xinghua. This is very impressive work for a pair of undergrads that were juggling a full course load, applying to grad school, etc., and more importantly, it is a great starting for our next experiments in the quantum realm.

Driving the radium ion's optical clock transition

Thu, 19 Dec 2019 00:00:00 +0000

Craig Holliman’s paper has come out in PRA. In this work Craig has realized the first driving of 3 transitions in any radium isotope, including the narrow (1 Hz) linewidth S_1/2 → D_5/2 optical clock transition. The radium ion is a very appealing clock candidate, the high mass is favorable because it simply moves less compared to other lighter elements in response to unwanted forces. It also has very photontic technology compatible wavelengths, the furthest in the blue is at a modest 468 nm, which can be generated directly from a diode laser. The other wavelengths for making an optical clock, 728 nm, 1079 nm and 802 nm, are similarly straightforward to generate from laser diodes. In addition to driving the clock transition Craig also drove the other narrow quadrupole transition from the ground state to the D_3/2 state at 828 nm. We are now planning to pursue coherent control of the clock transition with a laser stabilized to a high finesse optical cavity.

A measurement of and theory for radium's P_3/2 branching fractions

Fri, 06 Dec 2019 00:00:00 +0000

Our paper on the radium ion’s P_3/2 branching fractions was published in PRA. We did this work in collaboration with theorists Marianna Safronova and Sergey Porsev who made calculations of key matrix elements in the system, from which they obtain the P_3/2 branching fractions. The branching fractions tell you on average which of the three states (the S_1/2 ground state, and the D_3/2 and D_5/2 metastable states) are populated when the radium ion decays from the excited P_3/2 state. This first measurement of these branching fractions is necessary for a basic understanding of the system, such as calculating the dipole matrix elements that connect the electronic states. It was gratifying to see a nice agreement between measurements and theory in this work.

Strong optical forces paper appears in PRL

Fri, 19 Jul 2019 00:00:00 +0000

Xueping Long led the effort in Wes Campbell’s group to realize very strong optical forces that avoid the deleterious effects of spontaneous emission. A major issue in cold atoms and molecules is slowing a beam to speeds where the particles can be cooled and trapped. This often means scattering 100,000 photons or more. For molecules the photon scattering budget is limited by branching to excited vibrational states which, when populated, are essentially lost. This is the experimental realization of the force that we proposed for slowing molecular beams. The experimental work has been published in PRL.

Radium ion laser cooling published in PRL

Fri, 07 Jun 2019 00:00:00 +0000

The lab’s first paper, demonstrating the first laser cooling of the radium ion, was published in PRL. This has opened the door for us to make many first basic measurements of the ion and begin using the system for advanced applications and science. This paper also marks our lab’s first precision measurement: we measured the branching fractions of the excited P_1/2 state decays to the S_1/2 ground state and the D_3/2 metastable state. We are looking forward to exploring the element’s promise for quantum metrology and understanding basic symmetries of nature.

Post-bake coulomb crystals

Wed, 29 May 2019 00:00:00 +0000

Undergraduates Xiaoyang Shi and Michael Straus baked the ion trap to reach low pressures and were able to rapidly make the first Coulomb crystals in the lab’s second ion trap. To bake the system they took the entire trap off our optics table and placed it in a special oven. They then carefully ramped up the temperature and left the system pumping at high temperature. While the system was baking Xiaoyang and Michael improved the laser systems and experimental controls so that when the bake was finished they would be ready to go. To get back to trapping they had to move the system back to the optics table and set up the lasers that address our atoms. The image at right is a composite of a picture of 7 individual atoms that have been trapped and laser cooled and a computer rendering of the high-frequency trap used for this work. You can see where the ions are trapped in the center between all of the trap electrodes. Xiaoyang is now increasing control over the trapped ions by improving electronic, software, and laser hardware. Michael is setting up the 674 nm optical qubit laser and cavity for laser stabilization - a significant undertaking for a Sophomore.

The lab's second ion trap is operational

Fri, 12 Apr 2019 00:00:00 +0000

UC Santa Barbara undergraduate Xiaoyang Shi has gone from designing a high frequency (22 MHz) resonator a little under a year ago to developing, building, and now trapping ions in our second ion trap. In this work Xiaoyang was assisted by the lab’s graduate students and undergraduate Michael Straus. The image at right is a thermal cloud of trapped ions that is illuminated with a pair of laser beams. Xiaoyang trapped ions in a relatively low vacuum environment to test that the entire system is working before investing the time to bake the system to achieve low vacuum pressures where collision rates will be much lower. The picture, though not elegant, is incredibly exciting for an ion trapper - it shows that all of the different pieces have come together and are working in concert to trap and detect ions. For the lab this is our first foray into high frequency ion trapping, which is significantly more challenging than their low frequency counterpart. We were excited to find ions in a short 2 days from when Xiaoyang first turned on the lasers. The new trap is designed for quantum information science and quantum sensing. We are looking forward to increasing our control over the trapped ions and expanding our capabilities.

A portrait of a radium atom

Sun, 07 Oct 2018 00:00:00 +0000

Mingyu Fan took a photograph of a single radium ion scattering light as it hovered in free space where it was trapped by electric fields. In the primary picture you can see our vacuum chamber and trapping apparatus. When you look through the window of our vacuum chamber and zoom in to the highlighted yellow region you find floating in empty space (the black rectangle) a radium atom. The camera captures the light scattered by a radium ion over several pixels, resulting in the little blue dot in the center of the image.

Our research both studies and utilizes radium ions and it requires exacting levels of control. We need our ions to stay fixed in space for 10’s of hours so that we can both manipulate and detect the radium ion with laser light. For example, while holding the ion with electric fields we apply two lasers at different wavelengths, 468 nm (the blue light in the picture) and 1079 nm (infrared light that is invisible to your eye), to laser-cool the ion. This level of control requires a lot of careful work and creativity, primarily by Mingyu and Craig.

A challenge of portrait photography is getting your subject to stay still under the proper conditions, etc. With the time that has been put into our scientific apparatus it is easy (now!) to have our subject sit still, typically for an entire night of automated measurements, and the only remaining challenge is keeping the camera steady for a long exposure to collect the faint bits of light emitted from a single radium atom.

Unlike most atoms you might be familiar with radium is radioactive. This means you are looking at a picture of a young atom (it has not decayed yet). This particular isotope, radium 226, has a half-life of 1600 years, so it is almost certainly older than you are, but probably younger than The Great Pyramid and definitely a little baby compared to the dinosaurs.

Radium ions!

Thu, 26 Jul 2018 00:00:00 +0000

Mingyu and Craig trapped and, for the first time, laser cooled radium ions! The image shows one of the first trapped and laser cooled radium ions from our lab - yes, that is a picture of a single radium atom. Radium is famously radioactive, but the great scientific value is the high mass of the nucleus and its large octupole deformation. The special nucleus allows us to study nuclear physics as well as particle physics with our trapped radium ions. Because the atom has not been laser cooled there are a lot of basic electronic structure measurements to make. We’ll then study the radium nucleus as well as make massive molecular ions with our trapped radium ions for precision measurements. Our ion trap allows us to simultaneously load and trap radium and strontium ions, providing a platform to explore both species and the richness that comes with trapping and laser-cooling two alkaline earth atoms.

Working with a radioactive material in a modest research laboratory requires special techniques and tools. Our effort greatly benefited from much specialized equipment that comes from collaborations with UCLA and UC Berkeley. We are particularly grateful for the time-of-flight mass spectrometer that was designed and developed by Christian Schneider and the Einzel lenses and trap designed by Dave Hucul

Phonon lasing with trapped ions

Wed, 25 Jul 2018 00:00:00 +0000

Laser cooling of a single trapped ytterbium ion with the doubled light of an optical frequency comb was demonstrated in the Campbell Lab. Phonon lasing of the trapped ion between pairs of comb teeth was studied, and it was found that red comb tooth prevented the blue tooth from driving the ion beyond a certain amplitude. Frequency doubled (or quadrupled) light from freuqency combs is currently the only way to generate light in the deep ultraviolet to address transitions in important species such as He+. Crucially, the Campbell Lab used the doubled comb light to load and crystallize hot ions which opens the door to working with ions such as He+.

We have trapped ions!

Tue, 15 Aug 2017 00:00:00 +0000

We saw our first signal of trapped strontium ions on August 15th. The trap lifetime was limited by background gas collisions because the plan was to bake after loading our first ions. Post bake we were able to laser cool to generate crystals of trapped ions. The image shows a chain of 17 trapped strontium ions. We are working on our electronics and control to compensate for stray electric fields to reduce excess micromotion so that we can pursue our science goals.

Everyone in the lab contributed to this effort, including significant contributions from the lab’s undergrads: Alexander James setup the 405 nm photoionization laser as well as other optics. Sam Dutt made and characterize the neutral strontium oven and Jack Roten meticulously cleaned our vacuum parts.

Welcome Jared Pagett

Mon, 10 Apr 2017 00:00:00 +0000

UCSB undergraduate Jared Pagett joins the group.